Sharif Digital Repository

Due to the advantages of multi-agent systems, research in this area and the use of these systems in industry are increasingly growing. Applying these robots, various complex tasks can be done faster, safer and with better results. In our country, many different algorithms have been proposed and simulated, but due to the lack of a real environment for implementation, their actual performance has not been assessed. This project aims to create a platform for research and development of this field. This goal is achieved by performing the first phase of implementation, namely the design and construction of the robot platform. In the first step, qualitative and quantitative characteristics of the... 

In the present thesis, the movement of the clusters of fullerenes and nanocars are separately investigated on graphene surface, using molecular dynamics simulations. Investigating the fullerene clusters with different populations, it is concluded that, as the number of molecules inside the cluster increases, the displacement range of the motion decreases. In fact, some parts of the energy of the fullerene cluster are wasted through the intermolecular interactions, and as a result, the mobility of the cluster diminishes. During the investigation of the three-dimensional structures of fullerene, the wetting property of the clusters is revealed relative to the graphene surface. The decrease of... 

Synthetic polymers have a high capacity to provide and manufacture the pieces used in tissue engineering. However, optimizing the biocompatibility, bioresorbableility and mechanical properties simultaneous with processability of material is complicated and requires a lot of effort at designing different parts of the system. On the other hand, due to existence of secondary bonds (such as metal-ligand coordination or hydrogen bond) supramolecular polymers are able to respond to some stimuli such as temperature, pH, or pressure, which is important in terms of dynamic nature of interaction between the living cells and the external matrix of cell. Recently there have been extensive studies on... 

This experimental work is of two parts. First, self-assembled monolayers of cysteamine was formed on the gold electrode surface which leaded to the formation of amine groups on the surface; then amine bond was formed between these amine groups and the carboxylic acid groups of acid treated multi-walled carbon nanotubes (MWCNTs). The modified electrode was used for voltammetric determination of dopamine in the presence of uric acid. In the second part, acid treated MWCNTs were decorated with ruthenium nanoparticles; then the resulting composite was used for surface modification with the exact same procedure as the first part. Ruthenium nanoparticles on the electrode surface were... 

We used spectroscopic techniques to study self-assembled structures based on nucleobases like G-quadruplexes and macrocycles. Also we used DOSY NMR technique to study hydrogen bonding network in alcohol solutions. First part of our results indicate thermodynamic stability and slow kinetic of G-quadruplexes in apolar aromatic solvents like toluene. Also our results show easy monitoring of formation of each K+ or Na+ complex by NMR, due to the low solubility of alkaline metal salts in apolar media and possibility to stop at any given time in order to control G-quadruplex yield. When combined with suitable functional units, these valuable attributes may be used for the noncovalent synthesis of... 

Today, robots have been widely used in various tasks. Swarm robots are the focus of many researchers because of their low cost and their flexibility. However, due to the nature of dynamics in water and locomotion systems in it, very few of them have been developed. Applications of Swarm Robotics at sea include: the formation of temporary sea bridges, the collection of marine litter, assistance to large ships for maneuvering in ports, and carrying of oceanographic sensors. Therefore, the purpose of this study is to design a system for self-control and autonomy of unmanned surface robots with the ability to connect and carry objects. First, the robot was modeled according to its hydrodynamic... 

Self-Assembled Monolayer (SAM) is the first step in all surface engineering and assembly processes. It is used in sensor fabrication, memories and molecular recognition and optoelectronic devises as an active surface for patterning and chemical architecting of solid substrates. Tetraphenyl porphyrins because of their high stability and uniqe electronic and optic properties, that comes from their conjugate π electrons, easily can be used in these monolayers. Moreover they have a wide application because of their ability for coordination with metals and accepting substituents with electron donating and withdrawing properties. Electron transport through these layars which attach to the surface... 

Malaria is one of the most important infectious diseases in the tropical and subtropical regions of the world and is caused in humans by the bite of the female Anopheles mosquito of five species of Plasmodium. According to the World Health Organization, about 229 million people worldwide were infected in 2019 by the disease, and 409,000 people died from the disease. Resistance of the parasite against drugs and resistance of vectors to insecticides and larvicides, which prevents the elimination and eradication of malaria, shows the need for new strategies, such as having an effective vaccine against this disease. In the second generation of vaccines, to develop malaria vaccines, recombinant... 

Dye sensitized solar cells (DSCs) are among the 3rd generation solar cells which their mechanism of light absorption is similar to chlorophyll in green leafs and is based on photo-excitation of dyes. The electron-hole pairs of photo-excited dye separate at the interface of mesoporous semiconductor-dye-electrolyte. One of the approaches to increase the light path length and therefore the light harvesting efficiency in DSC is the addition of light scatterers inside the mesoporous semiconductor (photoanode).In this research, nanoparticulated hollow TiO2 fibers are introduced as novel light scatterers in DSCs with simultaneous light scattering, light trapping and high surface area. Light... 

Self-Assembly (SA) plays a critical role in the formation of different phenomena in nature. This phenomenon can be defined as an arrangement of meaningful patterns with the aggregate behavior of simpler structures. One of the examples of Self-Assembly can be considered of the formation of ice crystals from ice molecules. Previous works mainly focus on graph grammar and self-assembly in fully observable environments. These algorithms mainly consist of two main stages: first, constructing simpler structures and then joining these simpler structures to form a complex structure. The challenges of the previous work can be considered as the necessity of a central controller in the formation of... 

These days, self-assembly is one of the most significant phenomena in chemistry and biology. Although There are some Experiments and Simulations which help us to understand self-assembly much more than before, their mechanism is poorly understood. As a result, Calculating Free-energy landscape could be a great development in this area.We use the Flat-histogram monte Carlo algorithm to calculate the density of states of a complex system. In this way, there is a comparison between the exact density of states of Ising Model and the same quantities that are obtained from Flat histogram Method. After that, there would be a combination of statistical thermodynamics and Graph theory toward drawing... 

The Mesoporous Titanium Dioxide film using Sol-Gel method and Evaporation-Induced Self-Assembly technique (EISA) was prepared. In this study, in order to employ the best coatings in anode electrode of dye-sensitized solar cell, different conditions of making this film, the effective parameters in final structure, and various methods of coating were analyzed. After optimizing the conditions of film creating, images of field emission scanning electron microscope (FESEM) proved the formation of a layer of mesoporous structure which thickness after three times of coating is about 1.5 micrometers. In order to increase the energy conversion efficiency of solar cells, a new formulation for... 

A nematic colloid is a mixture of microscopic particles dispersed in a nematic liquid crystal (NLC), which is an anisotropic fluid with long-range orientational order. This long-range order might be perturbed due to different reasons, such as confinement between flat or curved surfaces which leads to frustration of the nematic director in some singular points or lines called ”topological defects”. The nucleation and the structure of these defects emerge from the elastic properties of NLC and leads to unique behavior of nematic colloids. The interaction between colloidal particles in simple fluids are mainly excluded volume interactions, electrostatic interactions, van der Waals interactions,... 

Enhancing the detection range, sensitivity and stability of phototdetectors due to their vast applications are in great importance. In recent years, Lead sulfide quantum dots, in order to their absorption over a wide range of wavelengths including Near-infrared (NIR), multiple exciton generation effect and solution processability are promising materials.However, long organic surface ligands which are necessary in synthesis process can suppress the carrie transport and the common method to overcome this weakness, is ligand exchange process. In this way, using short organic ligands because of their low electron mobility and methylammonium lead iodide ligands in order to their instability,...